#pragma once

#define S11 7
#define S12 12
#define S13 17
#define S14 22
#define S21 5
#define S22 9
#define S23 14
#define S24 20
#define S31 4
#define S32 11
#define S33 16
#define S34 23
#define S41 6
#define S42 10
#define S43 15
#define S44 21

class CMD5
{
public:
	CMD5::CMD5(){init();}

	inline UINT rotate_left(UINT x, UINT n){return (x << n) | (x >> (32-n));}
	inline UINT F(UINT x, UINT y, UINT z){return (x & y) | (~x & z);}
	inline UINT G(UINT x, UINT y, UINT z){return (x & z) | (y & ~z);}
	inline UINT H(UINT x, UINT y, UINT z){return x ^ y ^ z;}
	inline UINT I(UINT x, UINT y, UINT z){ return y ^ (x | ~z);}
	inline void FF(UINT& a, UINT b, UINT c, UINT d, UINT x,  UINT s, UINT ac){a += F(b, c, d) + x + ac;a = rotate_left (a, s) +b;}
	inline void GG(UINT& a, UINT b, UINT c, UINT d, UINT x, UINT s, UINT ac){a += G(b, c, d) + x + ac;a = rotate_left (a, s) +b;}
	inline void HH(UINT& a, UINT b, UINT c, UINT d, UINT x, UINT s, UINT ac){a += H(b, c, d) + x + ac;a = rotate_left (a, s) +b;}
	inline void II(UINT& a, UINT b, UINT c, UINT d, UINT x, UINT s, UINT ac){a += I(b, c, d) + x + ac;a = rotate_left (a, s) +b;}

	
	UINT state[4];
	UINT count[2];     // number of *bits*, mod 2^64
	BYTE buffer[64];   // input buffer
	BYTE digest[16];
	BYTE finalized;
public:
	void init()
	{
		finalized = false;
		count[0] = 0;
		count[1] = 0;
		state[0] = 0x67452301;
		state[1] = 0xefcdab89;
		state[2] = 0x98badcfe;
		state[3] = 0x10325476;
	}
	void transform(BYTE block[64])
	{
		UINT a = state[0], b = state[1], c = state[2], d = state[3], x[16];

		decode(x, block, 64);

		/* Round 1 */
		FF (a, b, c, d, x[ 0], S11, 0xd76aa478); /* 1 */
		FF (d, a, b, c, x[ 1], S12, 0xe8c7b756); /* 2 */
		FF (c, d, a, b, x[ 2], S13, 0x242070db); /* 3 */
		FF (b, c, d, a, x[ 3], S14, 0xc1bdceee); /* 4 */
		FF (a, b, c, d, x[ 4], S11, 0xf57c0faf); /* 5 */
		FF (d, a, b, c, x[ 5], S12, 0x4787c62a); /* 6 */
		FF (c, d, a, b, x[ 6], S13, 0xa8304613); /* 7 */
		FF (b, c, d, a, x[ 7], S14, 0xfd469501); /* 8 */
		FF (a, b, c, d, x[ 8], S11, 0x698098d8); /* 9 */
		FF (d, a, b, c, x[ 9], S12, 0x8b44f7af); /* 10 */
		FF (c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */
		FF (b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */
		FF (a, b, c, d, x[12], S11, 0x6b901122); /* 13 */
		FF (d, a, b, c, x[13], S12, 0xfd987193); /* 14 */
		FF (c, d, a, b, x[14], S13, 0xa679438e); /* 15 */
		FF (b, c, d, a, x[15], S14, 0x49b40821); /* 16 */

		/* Round 2 */
		GG (a, b, c, d, x[ 1], S21, 0xf61e2562); /* 17 */
		GG (d, a, b, c, x[ 6], S22, 0xc040b340); /* 18 */
		GG (c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */
		GG (b, c, d, a, x[ 0], S24, 0xe9b6c7aa); /* 20 */
		GG (a, b, c, d, x[ 5], S21, 0xd62f105d); /* 21 */
		GG (d, a, b, c, x[10], S22,  0x2441453); /* 22 */
		GG (c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */
		GG (b, c, d, a, x[ 4], S24, 0xe7d3fbc8); /* 24 */
		GG (a, b, c, d, x[ 9], S21, 0x21e1cde6); /* 25 */
		GG (d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */
		GG (c, d, a, b, x[ 3], S23, 0xf4d50d87); /* 27 */
		GG (b, c, d, a, x[ 8], S24, 0x455a14ed); /* 28 */
		GG (a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */
		GG (d, a, b, c, x[ 2], S22, 0xfcefa3f8); /* 30 */
		GG (c, d, a, b, x[ 7], S23, 0x676f02d9); /* 31 */
		GG (b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */

		/* Round 3 */
		HH (a, b, c, d, x[ 5], S31, 0xfffa3942); /* 33 */
		HH (d, a, b, c, x[ 8], S32, 0x8771f681); /* 34 */
		HH (c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */
		HH (b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */
		HH (a, b, c, d, x[ 1], S31, 0xa4beea44); /* 37 */
		HH (d, a, b, c, x[ 4], S32, 0x4bdecfa9); /* 38 */
		HH (c, d, a, b, x[ 7], S33, 0xf6bb4b60); /* 39 */
		HH (b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */
		HH (a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */
		HH (d, a, b, c, x[ 0], S32, 0xeaa127fa); /* 42 */
		HH (c, d, a, b, x[ 3], S33, 0xd4ef3085); /* 43 */
		HH (b, c, d, a, x[ 6], S34,  0x4881d05); /* 44 */
		HH (a, b, c, d, x[ 9], S31, 0xd9d4d039); /* 45 */
		HH (d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */
		HH (c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */
		HH (b, c, d, a, x[ 2], S34, 0xc4ac5665); /* 48 */

		/* Round 4 */
		II (a, b, c, d, x[ 0], S41, 0xf4292244); /* 49 */
		II (d, a, b, c, x[ 7], S42, 0x432aff97); /* 50 */
		II (c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */
		II (b, c, d, a, x[ 5], S44, 0xfc93a039); /* 52 */
		II (a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */
		II (d, a, b, c, x[ 3], S42, 0x8f0ccc92); /* 54 */
		II (c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */
		II (b, c, d, a, x[ 1], S44, 0x85845dd1); /* 56 */
		II (a, b, c, d, x[ 8], S41, 0x6fa87e4f); /* 57 */
		II (d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */
		II (c, d, a, b, x[ 6], S43, 0xa3014314); /* 59 */
		II (b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */
		II (a, b, c, d, x[ 4], S41, 0xf7537e82); /* 61 */
		II (d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */
		II (c, d, a, b, x[ 2], S43, 0x2ad7d2bb); /* 63 */
		II (b, c, d, a, x[ 9], S44, 0xeb86d391); /* 64 */

		state[0] += a;
		state[1] += b;
		state[2] += c;
		state[3] += d;

		// Zeroize sensitive information.
		memset((LPBYTE)x, 0, sizeof(x));
	}
	void encode(LPBYTE output, PUINT input, UINT len) 
	{
		//UINT i, j;

		for( UINT i = 0, j = 0; j < len; i++, j += 4 ) 
		{
			output[j]   = (BYTE)  (input[i] & 0xff);
			output[j+1] = (BYTE) ((input[i] >> 8) & 0xff);
			output[j+2] = (BYTE) ((input[i] >> 16) & 0xff);
			output[j+3] = (BYTE) ((input[i] >> 24) & 0xff);
		}
	}
	void decode(PUINT output, LPBYTE input, UINT len)
	{
		for( UINT i = 0, j = 0; j < len; i++, j += 4 )
		{
			//output[i] = MAKELONG(MAKEWORD(input[j], input[j+1]), MAKEWORD(input[j+2], input[j+3]));
			output[i] = ((UINT)input[j]) | (((UINT)input[j+1]) << 8) | (((UINT)input[j+2]) << 16) | (((UINT)input[j+3]) << 24);
		}
	}
	void update(LPBYTE input, UINT input_length) 
	{
		UINT input_index, buffer_index;
		UINT buffer_space;                // how much space is left in buffer

		if( finalized ) {
			return;
		}

		// Compute number of bytes mod 64
		buffer_index = (UINT)((count[0] >> 3) & 0x3F);

		// Update number of bits
		if(  (count[0] += ((UINT)input_length << 3)) < ((UINT)input_length << 3) ) {
			count[1]++;
		}

		count[1] += ((UINT)input_length >> 29);


		buffer_space = 64 - buffer_index;  // how much space is left in buffer

		// Transform as many times as possible.
		if( input_length >= buffer_space ) 
		{
			// fill the rest of the buffer and transform
			memcpy (buffer + buffer_index, input, buffer_space);
			transform(buffer);

			// now, transform each 64-byte piece of the input, bypassing the buffer
			for( input_index = buffer_space; input_index + 63 < input_length; input_index += 64 ) {
				transform (input+input_index);
			}
			buffer_index = 0;  // so we can buffer remaining
		}
		else
		{
			input_index = 0;     // so we can buffer the whole input
		}
		memcpy(buffer+buffer_index, input+input_index, input_length-input_index);
	}
	void finalize()
	{
		BYTE bits[8];
		UINT index, padLen;
		static BYTE PADDING[64] = 
		{
			0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
			0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
			0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
		};

		if( finalized ){
			return;
		}

		// Save number of bits
		encode(bits, count, 8);

		// Pad out to 56 mod 64.
		index = (UINT) ((count[0] >> 3) & 0x3f);
		padLen = (index < 56) ? (56 - index) : (120 - index);
		update (PADDING, padLen);

		// Append length (before padding)
		update(bits, 8);

		// Store state in digest
		encode(digest, state, 16);

		// Zeroize sensitive information
		memset(buffer, 0, sizeof(*buffer));

		finalized = true;

	}
	char *hex_digest()
	{
		char *s = new char[33];

		if (!finalized){
			return "";
		}

		for( int i = 0; i < 16; i++ ) {
			wsprintf(s+i*2, "%02x", digest[i]);
		}

		s[32]='\0';

		return s;
	}
};